The man, in his fifties, was treated by LAS, but died at the scene at 12.45am this morning.

A post-mortem examination will be held in due course, and next of kin have not yet been informed, police said.

They believe they know the identity of the deceased, but are awaiting formal identification.

Officers from the Homicide and Major Crime Command are leading the investigation into the murder.

There has been no arrest at this early stage, police said.

An incident room has opened at Putney under Detective Chief Inspector Nicola Wall.

Anyone with information that may assist the investigation should call the incident room on 020 8785 8963. To remain anonymous call Crimestoppers on 0800 555 111.

This incident comes after Britain's most senior police officer Sir Bernard Hogan-Howe expressed concern over the number of stabbings at last weekend's Notting Hill Carnival, which is Europe's biggest street festival, saying some were centimetres from being murder.